Large South American snake (8)

I think it could be either:

Which length description are you looking for?:

anaconda

'large south american snake' is the definition.
(I've seen this before)

This is all the clue.

(Other definitions for anaconda that I've seen before include "large reptile" , "A slippery customer" , "crawler" , "Large South American snake" , "Large water snake" .)

I've seen this clue in the Sydney Morning Herald.

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